The actor-director-producer and his colleagues also discuss creating a modern movie about the titular daydreamer and the status of the "Zoolander" sequel.

In The Secret Life of Walter Mitty, Ben Stiller's character lives in both the real world and a fantasy realm in which he imagines himself doing extraordinary things. Working on the film, Stiller was juggling three roles: actor, director and producer, which was an extraordinary feat in and of itself, according to those who worked with him.

"He wore 50 hats, and I still don't know how he did it. I'm convinced he had a clone or something," co-star Kristen Wiig told The Hollywood Reporter at Mitty's New York Film Festival premiere Saturday night.

Fellow cast members Adam Scott and Adrian Martinez found Stiller's ability to handle his various roles in the film inspiring.

"He was just overwhelmingly meticulous about every detail in the movie and invested in his fellow actors and running a show of this size and being present over everything," Martinez said.

Stiller's producing partner Stuart Cornfeld told THR that on films in which Stiller's also acting and directing, there's more prep work ahead of time so he can focus on acting while he's on set.

"There's more preparation because it's very important to him that when he's acting, he can spend as much energy on acting as possible, which means that during the prep of the movie, a lot of the questions that you would normally figure out on the day, he wants to work out," Cornfeld explained.

Stiller said that while he approaches every film the same way, this one had a different tone than his broad comedies like Tropic Thunder and Zoolander.

"I think every movie's different, but I kind of approach them all the same way. It becomes a very full investment of everything," he said. "This movie was different, I guess, because it was a different kind of movie in terms of the tone, maybe, and a movie that wasn't necessarily completely judged on the laughs. So looking at the movie that way, when I'd look at a scene, it was interesting to say, oh well, this scene doesn't have to be that funny. It's really about something else, and I'm used to, the last few movies that I've directed have been pretty broad comedies, so to have a different criteria was really interesting."

The film is also significantly different from both the 1947 movie of the same name, starring Danny Kaye, and the James Thurber short story upon which both were based. Stiller's movie expands upon the short story and features a more linear, modern narrative than the 1947 film.

Cast member Patton Oswalt said the concept of creating a 21st century Mitty was what attracted him to the project.

"How do you pull off a movie about a daydreamer, especially now, when we're all just daydreaming? I mean, we f---ing pay $500 to carry daydreams around," Oswalt told THR, pulling out his smartphone. "So that really pulled me in, like they're going to do Walter Mitty now, post-Twitter, post-Instagram? Let's see what they do."

Producer John Goldwyn, whose grandfather Samuel Goldwyn produced the original film, said having the film debut as the centerpiece gala screening at the festival allowed them to show that the new version of Walter Mitty is different from the ones that came before.

"The fact that the New York Film Festival selected us gave us the opportunity to have a real platform for the world to understand that the movie is different. It's not a remake. It's not a rehash of anything old," he explained.

The fact that the movie was filmed and takes place in Stiller's hometown also made it appropriate for a Gotham debut, Cornfeld told THR.

"Ben is a real New Yorker. We could have shot this movie in any city, but Ben was very insistent upon New York," Cornfeld said. "He feels an affinity for the city; he feels there's an energy -- all the New York stuff that he wanted to capture. And he felt that if you're going to tell the story of somebody who is not quite engaged in life, it is very good to put that person in an environment where there's so much life around."

The parts of the movie that weren't shot in New York were filmed in Iceland, and the extraordinary adventures Mitty has include some impressive stunts and special effects.

Fox film chief Jim Gianopulos told THR that after a summer that saw a number of big-budget movies struggle at the box office, he and his colleagues realized the importance of having strong, character-driven stories like this one beneath stunning visuals.

"I think what we learned is you can't just throw effects at the screen and hope it works. Sometimes they augment it and enhance a film, but ultimately, you have to have the underlying quality and story to make it work," he said.

Gianopulos, who's solely helmed Fox's film division since co-chairman Tom Rothman exited last year, also dismissed the recent wave of executive changes at the major studios, saying those shifts were merely coincidental.

He also refused to talk about rumors that former Warner Bros. film chief Jeff Robinov might wind up at Fox, saying simply, "I don't know what Jeff is going to do. I'm sure he'll find someplace where he'll be very happy."

Fans of Stiller's meanwhile, would likely be happy to see a sequel to his beloved 2001 film Zoolander, a project that's long been reported to be in the works.

Cornfeld and Stiller both said they had a great script for it but indicated that there may be other factors delaying the project.

When THR asked Cornfeld, who produced the original film and is set to produce the sequel, whether we'd see a Zoolander 2, he rolled his eyes and said, "It's not in my hands."

Stiller, meanwhile, said: "Possibly. … I do think that if I wait much longer, it will have to take place in a senior citizens' home. But, we'll see."